Upbeat. The only (released, not counting unreleased in which she has a few outstanding ballads) ballad of Gaga's I can say I truly like is Dope. (Gypsy and TEOG if power ballads count?)
Well my fave Katy song is a ballad (TOTGA) but my 2nd fave is California Gurls, so a mix of both. I guess I tend to favor darker, midtempo songs with big beats (Dark Horse, Radioactive, Dance Without You)